See perlre, or perlretut, or quotemeta or perlop on \Q...\E.

Can I use the code similar to this?

#!/usr/bin/perl

while ($line = <DATA>){
$line =~ s/<cc>([\s\S]+?)<\/cc>/defined ($1) ? "(&amp;amp;|&amp;)" : '
+-'/eg;
print $line;
}
[download]

This prints out (&|&). But replacing of & and & doesnot gets replaced with '-'.

Is this a different question to your original question? I don't understand it. The data in your original question does not have <cc> in it.

//g switch in above regexp doesn't make sense, can be omitted.

I have been thinking intensively for a moment, but cannot find any example, where it would be better than

What exactly is this code supposed to do?

grizzley I couldn't agree more...

Corion fixes the original Unmatched ( in regex; marked by <-- HERE in m/fg-&amp;amp;&amp;+(and( <-- HERE we- error,
but beyond that i am struggling...

#!/usr/bin/perl

use warnings;
use strict;

while(my $line=<DATA>){

my $name_pre=$line;
my$name=$line;
print "1: name $name * name_pre $name_pre \n";
$name=~ s/&amp;amp;/-/g;
print "2: name $name * name_pre $name_pre \n";
$name=~ s/&amp;/-/g;
print "3: name $name * name_pre $name_pre \n";

$name =~ s/-$//;
print "4: name $name * name_pre $name_pre \n";

$name_pre=~ s/\Q$name_pre\E/\Q$name\E/g;
print "5: name $name * name_pre $name_pre \n";

$name_pre =~ s/\\//g;
print "6: name $name * name_pre $name_pre \n";

}
__DATA__
fg-&amp;amp;&amp;+(and(we-
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Prints:


1: name fg-&&+(and(we-
 * name_pre fg-&&+(and(we-
 
2: name fg--&+(and(we-
 * name_pre fg-&&+(and(we-
 
3: name fg---+(and(we-
 * name_pre fg-&&+(and(we-
 
4: name fg---+(and(we
 * name_pre fg-&&+(and(we-
 
5: name fg---+(and(we
 * name_pre fg\-\-\-\+\(and\(we\
 
6: name fg---+(and(we
 * name_pre fg---+(and(we
[download]

Just a something something...

The actual program code is below:

Open FH,’file.txt’;
               while (<$FH>) {
                      $arr[$i].="$_";
               }
               close ($FH);
            $text=$arr[$i];
            $text =~ /<cc>([\s\S]+?)<\/cc>/;
            $Name_pre=$1;
            $Name=$1;
$Name=~ s/&amp;amp;/-/g;
$Name=~ s/&amp;/-/g;
$Name =~ s/-$//g;
            $st=$Name;
            $char=chop($st);
            if($char eq '-')
              {$Name=~ s/$//g;}
            $arr[$i]=~ s/$Name_pre/$Name/g;
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Is it the right way of coding. When I execute the program with the $Name_pre as

fg-&&+(and(we-
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the program terminates giving an error at the line

  $arr[$i]=~ s/$Name_pre/$Name/g;
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as

Unmatched ( in regex; marked by <-- HERE in m/fg-&amp;amp;&amp;+(and( 
+<-- HERE we-
/
[download]

There are many other problems in the script as presented, but you immediate problem can probably be solved by changing the offending line to:

$arr[$i]=~ s/\Q$Name_pre\E/$Name/g;
[download]

---

True laziness is hard work

Take a look at perlre for more info and the opportunity to learn, but basically you'll either have to escape them using backslashes or use \Q \E to contain your $Name_pre string, though as pointed out above, why are you assigning the value in such an odd way?

you could substitute all ( in a string with the regex $string =~ s/\(/$cheesesauce/g;

Oh Goddess, look this code needs a lot of work, take a look at the following

open($FH,'<','file.txt');
$arr[$i]=join('',(<$FH>));
close ($FH);
$arr[i] =~ /<cc>([\s\S]+?)<\/cc>/$1/;
$arr[i] =~ s/&amp;amp;/-/g;
$arr[i] =~ s/&amp;/-/g;
$arr[i] =~ s/\(/-/g; # I assume
$arr[i] =~ s/-$//;
if (substr($arr[i],-1,1) eq '-') {
   $arr[i]=~ s/-$//g; # I assume you meant, though you've already done
+ it above
}
[download]

I'm sure it's far from perfect, but an improvement on your current code nonetheless